diff options
| -rw-r--r-- | arch/powerpc/lib/code-patching.c | 107 | ||||
| -rw-r--r-- | include/asm-powerpc/code-patching.h | 8 |
2 files changed, 115 insertions, 0 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 430f4c15d78..27957c4ea9e 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -41,3 +41,110 @@ unsigned int create_branch(const unsigned int *addr, return instruction; } + +unsigned int create_cond_branch(const unsigned int *addr, + unsigned long target, int flags) +{ + unsigned int instruction; + long offset; + + offset = target; + if (! (flags & BRANCH_ABSOLUTE)) + offset = offset - (unsigned long)addr; + + /* Check we can represent the target in the instruction format */ + if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3) + return 0; + + /* Mask out the flags and target, so they don't step on each other. */ + instruction = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC); + + return instruction; +} + +static unsigned int branch_opcode(unsigned int instr) +{ + return (instr >> 26) & 0x3F; +} + +static int instr_is_branch_iform(unsigned int instr) +{ + return branch_opcode(instr) == 18; +} + +static int instr_is_branch_bform(unsigned int instr) +{ + return branch_opcode(instr) == 16; +} + +int instr_is_relative_branch(unsigned int instr) +{ + if (instr & BRANCH_ABSOLUTE) + return 0; + + return instr_is_branch_iform(instr) || instr_is_branch_bform(instr); +} + +static unsigned long branch_iform_target(const unsigned int *instr) +{ + signed long imm; + + imm = *instr & 0x3FFFFFC; + + /* If the top bit of the immediate value is set this is negative */ + if (imm & 0x2000000) + imm -= 0x4000000; + + if ((*instr & BRANCH_ABSOLUTE) == 0) + imm += (unsigned long)instr; + + return (unsigned long)imm; +} + +static unsigned long branch_bform_target(const unsigned int *instr) +{ + signed long imm; + + imm = *instr & 0xFFFC; + + /* If the top bit of the immediate value is set this is negative */ + if (imm & 0x8000) + imm -= 0x10000; + + if ((*instr & BRANCH_ABSOLUTE) == 0) + imm += (unsigned long)instr; + + return (unsigned long)imm; +} + +unsigned long branch_target(const unsigned int *instr) +{ + if (instr_is_branch_iform(*instr)) + return branch_iform_target(instr); + else if (instr_is_branch_bform(*instr)) + return branch_bform_target(instr); + + return 0; +} + +int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr) +{ + if (instr_is_branch_iform(*instr) || instr_is_branch_bform(*instr)) + return branch_target(instr) == addr; + + return 0; +} + +unsigned int translate_branch(const unsigned int *dest, const unsigned int *src) +{ + unsigned long target; + + target = branch_target(src); + + if (instr_is_branch_iform(*src)) + return create_branch(dest, target, *src); + else if (instr_is_branch_bform(*src)) + return create_cond_branch(dest, target, *src); + + return 0; +} diff --git a/include/asm-powerpc/code-patching.h b/include/asm-powerpc/code-patching.h index a45a7ff7872..40ad46b1dd9 100644 --- a/include/asm-powerpc/code-patching.h +++ b/include/asm-powerpc/code-patching.h @@ -23,9 +23,17 @@ unsigned int create_branch(const unsigned int *addr, unsigned long target, int flags); +unsigned int create_cond_branch(const unsigned int *addr, + unsigned long target, int flags); void patch_branch(unsigned int *addr, unsigned long target, int flags); void patch_instruction(unsigned int *addr, unsigned int instr); +int instr_is_relative_branch(unsigned int instr); +int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr); +unsigned long branch_target(const unsigned int *instr); +unsigned int translate_branch(const unsigned int *dest, + const unsigned int *src); + static inline unsigned long ppc_function_entry(void *func) { #ifdef CONFIG_PPC64 |